This invention relates generally to the field of telephony, and more particularly to an improved device enabling the transfer of switching operations for individual circuits from a first location to a second location without more than momentary interruption of service to an individual subscriber.
The problem of transferring switching operations for existing telephone circuits is a continuous one. With constant growth of the number of subscribers in a given area, the limit of physical capacity of an existing telephone office is often reached within a few years of the date of initial operation. Very often it is not possible, or economically feasible, to expand existing facilities, and to provide for additional subscriber circuits, an entirely new office is constructed at a new location with the intention that switching functions for some if not all of the circuits previously served at the old location will be transferred to the new location. Since the transfer, if accomplished on an individual circuit-by-circuit basis will result in substantial interruption of service, it is desirable, ideally, to accomplish the changeover on a substantially instantaneous basis in which large blocks of subscriber circuits are transferred simultaneously.
In U.S. Pat. No. 3,872,259 granted Mar. 22, 1977, and assigned to the same assignee as the instant application, there is disclosed a device for accomplishing the transfer of large blocks of circuits instantaneously, using electronic elements. Once the transfer has been effected, the device may be disconnected and reused for a similar function, and where large numbers of such transfers in a given geographic area are required over a relatively short period of time, the cost of such devices may be readily justified.
However, in many areas of relatively lesser population density, the problem arises on a smaller scale, and a reusable device of lesser complexity will accomplish an equivalent result at correspondingly less cost.